Morphological and Molecular Characterization of Earthworms (Oligochaeta, Annelids) in Kurdistan Region of Iraq


The present study was designed to identify the earthworms in Kurdistan Region of Iraq. To meet the requirements of the study, 395 individuals of earthworms were collected in 43 locations from July 2018 through April 2019 in Erbil, Sulaymaniyah, Duhok and Halabja provinces. Worms were obtained from gardens, moist soils, agricultural area, on mountains, and small forests. Annelid worms were picked up from soil by hand-storing method. Identification of worm specimens was based on morphological features of adult worms followed by molecular analyses.

 Morphological identification of adult worms was based on external characters such as Body length, number of segments, clitellum situation, arrangement of setae and shape of prostomium. Moreover, internal characters such as presence or absence of both calciferous gland and seminal vesicles, number and location of spermathecae, position of crop and gizzard were exploited to recognize worms as well. According to our results, four genera and nine species of earthworms were identified.

Molecular analyses of morphologically-identified specimens was conducted to confirm the authenticity of worm recognition. In this regard, mitochondrial DNA (mtDNA) used for this purpose. Cytochrome-C oxidase I (COI) gene selected for this study because gene mutation is rare. The extracted mtDNA from caudal tissue was used for the molecular analysis. The mtDNA samples were sent to the BM labosis company in Ankara/Turkey for performing the sequencing processes.

DNA sequences subjected to Nucleotide Basic Local Alignment Search Tool (BLAST) in NCBI Gen Bank. Having said, nine species belonging to two families and four genera were identified as following: 1-Lumbricidae; Aporrectodea (A.) longa, A. trapezoides, A. rosea, Lumbricus (L.)  terrestris, L. rubellus and Haelyella (H.) syriacae. 2- Megascolecidae; Amynthas (Am.) morrisi, Am. gracilis, and Am. luridus.

In the light of the current results, the species H. syriaca, Am. gracilis and Am. luridus are deemed as the first records in Iraq.